Can Sparkling Water Increase Your Risk of Colorectal Cancer?
Sparkling water has spent the last decade marketed as the smart swap for soda. Zero sugar, zero calories, all the fizz.
So when social media started suggesting that very same can might be linked to colorectal cancer, the reaction was immediate.
The claims spread fast on TikTok and Instagram. Canned sparkling water, influencers said, contains undisclosed chemicals and dangerously high levels of so-called "forever chemicals."
Searches for sparkling water and cancer climbed within days.
The real story is more complicated than either the panic or the dismissal suggests. Here's what colorectal cancer specialists and the published research actually say.
It's Not the Water. It's the Can.
The first thing worth clearing up: when doctors talk about a possible cancer concern with sparkling water, they are not talking about carbonation itself.
It's not anything inherent to seltzer as a beverage.
The concern centers on PFAS — per- and polyfluoroalkyl substances, often called "forever chemicals" because they don't break down in the environment or the human body.
PFAS are used in a wide range of industrial and consumer products. That includes the linings of some beverage cans, food packaging, non-stick cookware, and water-resistant fabrics.
Dr. Steven Lee-Kong, division chief of colorectal surgery at Hackensack Meridian Health's Hackensack University Medical Center, told HuffPost that the worry isn't about the carbonated drink itself. It's about the containers these drinks are typically packaged in.
That distinction matters. A glass bottle of sparkling water and a can of sparkling water are not equivalent from a PFAS-exposure standpoint.
The can lining is the actual source of potential contamination, not the water or the bubbles.
What the Research on PFAS and Colorectal Cancer Actually Shows
PFAS exposure has been studied for years in connection with several types of cancer. The picture for colorectal cancer specifically is still taking shape.
Research has more firmly linked PFAS to higher risk of kidney cancer and testicular cancer. It's also tied to other health effects including impaired immune function, liver damage, fertility problems, and thyroid disease.
The evidence connecting PFAS specifically to colorectal cancer is less settled.
A narrative review published through Yale's School of Public Health examined both epidemiological studies and laboratory research on PFAS and colorectal cancer. The review found that animal and cell-line studies show mixed results.
Some studies suggest molecular disruptions that could promote tumor development. Others show no clear effect, and at least one line of research even points to an inverse association in certain contexts.
A separate review published in the journal Frontiers in Toxicology focused on PFOS, one of the most studied PFAS compounds, and its relationship to intestinal inflammation. The researchers noted that PFOS exposure has been associated with gastrointestinal inflammation contributing to ulcerative colitis, a condition already recognized as a precursor to colorectal cancer in some patients.
But the review was explicit that direct evidence linking PFOS to colorectal cancer itself remains limited and has produced contradictory findings across different studies.
Laboratory research published in the journal Environmental Pollution found that PFOS exposure could promote the migration of colorectal cancer cells in cell-line experiments. This happens through a cellular process called epithelial-mesenchymal transition that's associated with tumors becoming more invasive.
This kind of cell-line study demonstrates a plausible biological mechanism. But it doesn't establish that drinking PFAS-containing beverages at real-world exposure levels produces the same effect in actual human colons.
Why Doctors Are Still Concerned, Even Without a Clear Verdict
Dr. Lee-Kong explained to HuffPost that the working theory centers on PFAS promoting gut inflammation and cellular changes. That represents the primary mechanism of concern for colorectal cancer risk specifically, while acknowledging that research is still ongoing and findings remain inconsistent.
That's a meaningfully different statement than "sparkling water causes cancer." It's closer to: there's a plausible biological pathway worth taking seriously, even though the evidence isn't yet strong enough to draw a firm conclusion.
Testing has found PFAS in some popular sparkling water brands. But the detected levels have generally fallen well below current federal advisory limits, according to Lee-Kong.
Other researchers in the same reporting noted that the dose matters considerably. The amount of PFAS that can leach from a beverage can is far below the levels shown to cause cancer in laboratory studies.
At the same time, some health organizations argue that even very low levels of PFAS exposure could carry some risk, since these chemicals accumulate in the body over years rather than being cleared quickly.
That's part of why the scientific conversation hasn't settled into a clean "safe" or "unsafe" verdict.
How Sparkling Water Compares to Other Established Risk Factors
It's worth placing this concern next to what's already well-established about colorectal cancer risk. The comparison puts the sparkling water question into useful context.
Research has built a much stronger and more consistent case linking colorectal cancer to several other dietary and lifestyle factors. That includes regular consumption of deli meats and other processed meats, alcohol intake, sugar-sweetened beverages, and ultra-processed foods more broadly.
These associations are supported by larger, more consistent bodies of evidence than the current PFAS-and-colorectal-cancer research.
That doesn't make the PFAS question irrelevant. It means that, based on current evidence, sparkling water sits well behind those more established risk factors in terms of how confident researchers are in any connection to colorectal cancer.
What This Means If You Drink Sparkling Water Regularly
If you're a regular sparkling water drinker wondering whether to change anything, here's a grounded way to think about it.
There is currently no direct evidence proving that canned sparkling water or seltzer causes colon cancer. The concern is based on a plausible biological mechanism involving PFAS and gut inflammation.
That mechanism is supported by some laboratory research. But it's not yet confirmed by strong human epidemiological data specific to colorectal cancer.
If reducing potential PFAS exposure feels worthwhile to you, a few practical options exist. Bottled sparkling water in glass packaging avoids the can-lining exposure pathway entirely.
Looking into brands that publish independent PFAS testing results is another option. Some companies have begun disclosing this information as consumer interest has grown.
Varying your beverage choices, rather than relying on any single canned drink as your primary daily hydration source, is also a reasonable, low-effort step.
What's not supported by current evidence is treating sparkling water as an urgent health threat requiring immediate elimination. The dietary factors with the strongest established links to colorectal cancer remain the more actionable targets.
That means processed meat, alcohol, sugary drinks, and ultra-processed food, if reducing colorectal cancer risk through diet is the actual goal.
The science on PFAS and colorectal cancer specifically is still evolving. Researchers across multiple reviews have called for further study to resolve the inconsistent findings so far.
Until that research matures, the most accurate summary is the one doctors themselves have offered: a real question worth monitoring, not a settled answer.
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Tech & AI Editor
David Park covers artificial intelligence, Big Tech, and the future of digital innovation. He translates complex tech developments into stories that matter for everyday readers.
